# Add the root path of the pygra library
import os ; import sys 
sys.path.append(os.path.dirname(os.path.realpath(__file__))+"/../../../src")





from pygra import geometry
g = geometry.honeycomb_zigzag_ribbon(10) # create geometry of a zigzag ribbon
h = g.get_hamiltonian() # create hamiltonian of the system
h.add_anti_kane_mele(.1) # add Kane mele spin orbit coupling
h.get_bands(operator="sz") # calculate band structure






